Its working fine, but there's a problem. Your plugin conflicts with guiredeemmcmmo. When I try to run both plugin, since they have the same command /redeem and only the guiredeemmcmmo works. If will be better if you change the alias for the command. like /rcodes? Or something different?

This! This is the thing I've been looking for! Thank you for making it!
A nice and simple plugin, clean and neat. Really easy to use.
If I found any bugs/error I'll post it in discussion. Will try it now :D